Why six Chevy drivers had plenum fires in Indy 500 qualifying, and how the problem will be fixed

INDIANAPOLIS – Confirming six plenum fires during Indy 500 qualifying Saturday, Team Chevy executives said the manufacturer would be working around the clock and around the globe to fix the problem.

The Chevys of Kyle Larson, Pato O’Ward, Conor Daly, Christian Rasmussen, Ed Carpenter and Agustin Canapino had plenum fires during their four-lap qualifying runs, which were hindered by the ensuing loss of momentum when drivers were forced to lift off the accelerator.

Rasmussen and Canapino both failed to advance to the Fast 12 round Sunday because of their plenum events, which essentially constitute a misfire (often during downshifting) that causes a drop of engine torque. The only remedy is to lift off the accelerator to extinguish the small fire.

Syndication: The Indianapolis Star
Syndication: The Indianapolis Star

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“Our team is going to work here overnight, running our dyno facilities around the world,” GM vice president of performance and motorsports Jim Campbell said in a news conference after qualifying. “We're going to be running overnight and then we're working on ways to mitigate the issue and eliminate. (We will) aero proof it for tomorrow around controls and calibration.

“We're pushing as hard as we can. This year we have nine out of the Fast 12. Last year we had eight out of the Fast 12, but we did not get the pole last year, so we're pushing to get to the pole.”

IndyCar program manager Rob Buckner said the plenum events were the byproduct of pushing the envelope for greater performance and speed in a relatively unknown conditions. Indy 500 qualifying is conducted with an extra 100 horsepower from a turbo boost, and Campbell said Chevy had no testing with the new configuration prior to practice Friday.

Syndication: The Indianapolis Star
Syndication: The Indianapolis Star

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“It's definitely related to how hard we're operating these engines,” Buckner said. “I think it's easy to overlook how much engine performance has been gained throughout the years. A lot of times you come up with some really good gains. You show up here, and it's barely competitive. That's just a result of how hard us and our competitors push each other, how much the Indy 500 means as a manufacturer and as an engine program.

“This is judgment weekend for us. We want to bring big power. We want to be robust. We want to be reliable. We missed one little piece of it today, but to Jim's point, really proud of having nine of the top 12. I think we have a speed advantage, and we're just going to work as hard as we can going into tomorrow to finish executing the weekend.”

Before Saturday, the last instance of a plenum event having a major impact on an event was the 2023 season opener. O’Ward was leading the Firestone Grand Prix of St. Petersburg with three laps remaining when a plenum fire occurred in his No. 5, which fell to second with the subsequent loss of power.


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“We usually have them in practice when they're not so visible,” Buckner said. “But one of the things we love about the Indy 500, we don't hide from it. We're accountable for what goes on here, especially with the engine program. We're going to own it, good and bad, and learn from it, and come back tomorrow.”

Campbell noted that Chevrolet qualified all of its cars for the Indy 500 (the final three spots will be determined Sunday between four Dallara-Hondas) and added there was no harm to the engines that had the plenum fires.

Buckner said there were no signs of plenum events with the added turbo boost in Friday’s practice. Chevy expects there will be no issues after engines are detuned for Monday practice and through the May 26 race (which also will feature fresh engines).

“The incidence is much lower,” Campbell said. “Not to say it would never happen. But much lower.

It'll be a much smaller concern. But nonetheless, we don't want any driver to be affected by it.”

Results from Day 1:

1. (12) Will Power, Chevrolet, 2 minutes, 34.0053 seconds (233.758 mph)
2. (3) Scott McLaughlin, Chevrolet, 2:34.2863 (233.332)
3. (2) Josef Newgarden, Chevrolet, 2:34.3124 (233.293)
4. (7) Alexander Rossi, Chevrolet, 2:34.4609 (233.069)
5. (27) Kyle Kirkwood, Honda, 2:34.6634 (232.764)
6. (17) Kyle Larson, Chevrolet, 2:34.7965 (232.563)
7. (60) Felix Rosenqvist, Honda, 2:34.8074 (232.547)
8. (14) Santino Ferrucci, Chevrolet, 2:34.8415 (232.496)
9. (75) Takuma Sato, Honda, 2:34.8566 (232.473)
10. (5) Pato O’Ward, Chevrolet, 2:34.8826 (232.434)
11. (21) Rinus VeeKay, Chevrolet, 2:34.8930 (232.419)
12. (23) Ryan Hunter-Reay, Chevrolet, 2:34.9153 (232.385)
13. (26) Colton Herta, Honda, 2:34.9616 (232.316)
14. (10) Alex Palou, Honda, 2:34.9682 (232.306)
15. (6) Callum Ilott, Chevrolet, 2:35.0184 (232.230)
16. (11) Marcus Armstrong, Honda, 2:35.0504 (232.183)
17. (20) Ed Carpenter, Chevrolet, 2:35.1608 (232.017)
18. (4) Kyffin Simpson, Honda, 2:35.2069 (231.948)
19. (98) Marco Andretti, Honda, 2:35.2458 (231.890)
20. (06) Helio Castroneves, Honda, 2:35.2587 (231.871)
21. (9) Scott Dixon, Honda, 2:35.2723 (231.851)
22. (78) Agustin Canapino, Chevrolet, 2:35.2750 (231.847)
23. (41) Sting Ray Robb, Chevrolet, 2:35.2888 (231.826)
24. (33) Christian Rasmussen, Chevrolet, 2:35.3852 (231.682)
25. (66) Tom Blomqvist, Honda, 2:35.4554 (231.578)
26. (77) Romain Grosjean, Chevrolet, 2:35.4982 (231.514)
27. (8) Linus Lundqvist, Honda, 2:35.5034 (231.506)
28. (45) Christian Lundgaard, Honda, 2:35.5308 (231.465)
29. (24) Conor Daly, Chevrolet, 2:35.6803 (231.243)
30. (30) Pietro Fittipaldi, Honda, 2:35.7768 (231.100)